In flow cytometry, white blood cell (WBC) differential count, or the like, various cells, such as white blood cells, are classified in order to classify normal cells and abnormal cells. These tests have been used to test various diseases, and the accuracy thereof, i.e. correctly classifying different types of cells, is very important.
Korean Patent Laid-Open Publication No. 2005-094097 discloses a method for classifying cells, which includes: irradiating the cells using a laser beam source, such as a laser diode; collecting a distribution of scattered light according to a light scattering effect caused by the components of the cells, such as the nuclei, as the light passes through the cells; and classifying the cells based on the collected scattered light.
The above-described conventional technique classifies the types of cells by irradiating a single laser beam, providing a plurality of photodetectors at a portion to which the irradiated laser beam is directed through the cells, and measuring light density based on the angle of the optical path formed around the cells as the light is scattered, thereby identifying the cells.
However, according to the above-described technique, when the cells are moved on a movement path of laser beam for the classification of target cells, the distribution of the components of the cells may be changed as the cells rotate, and as a result, the density of light collected by the photodetectors at different angles may be changed even in the same cell as the laser is irradiated in a single direction. Therefore, it has been noted that the cells cannot be accurately classified.
In addition, since a single laser beam is used, there is a problem in that blood cells, which may be identified as different cells despite the same shape, cannot be properly analyzed and classified.
In addition, since a unidirectional laser is used, there is a problem in that a very limited number of types (e.g., five types of WBC) of cells can be classified, and as a result, the efficiency of cell classification is greatly reduced.